This invention relates to the control of an automatic climate control system for a motor vehicle, and more particularly to a control that is adaptively adjusted to reflect vehicle occupant preferences.
In vehicles equipped with an automatic climate control system, the driver or other occupant adjusts a xe2x80x9cset temperaturexe2x80x9d for the vehicle cabin, and an electronic control module responds in a pre-programmed way to control the blower speed, air discharge temperature and air delivery mode (outlet vent).
Typically, the control is based not only on the set temperature (Tset), but also on a number of measured parameters such as outside air temperature (Tamb), solar loading (Tsolar), and cabin air temperature (Tin-car). FIGS. 1A-1B illustrate a conventional control in which Tset, Tamb, Tsolar and Tin-car are combined with a constant K to form a Program Number (PN) for scheduling desired values of blower speed, air discharge temperature and air delivery mode. As indicated, PN decreases in response to increasing values of Tamb, Tsolar and Tin-car to provide increased cooling, and PN increases in response to increasing values of Tset to provide increased heating. The control responses illustrated in FIG. 1B are heuristically determined for occupant comfort at steady-state conditions, and an initial high or low value of Tin-car following a hot-soak or cold-soak condition has the effect of initiating a transient cool-down or heat-up period.
Obviously, the above-described approach (or any other pre-programmed approach) cannot satisfy every individual. In a given environmental condition, for example, some people are more comfortable with a low blower speed, while others are more comfortable with a high blower speed. For this reason, the system control panel includes an operator interface for overriding the automatic control settings; in such case, the overridden setting (blower speed, for example) is maintained until automatic control is re-instituted. However, the need for operator overriding negates the advantages of an automatic control, and it would be better if the automatic control settings could somehow adapt or automatically tune to the preferences of the operator. One such adaptive system is disclosed in the U.S. Pat. No. 5,511,724 to Freiberger et al., issued on Apr. 30, 1996 and assigned to the assignee of the present invention. In Freiberger et al., control adaptation based on operator overrides is achieved in the context of a program number (PN) control strategy by adjusting the constant K by an offset value adaptively determined based on operator adjustment of Tset, and adjusting the scheduled blower speed by an offset value adaptively determined based on operator override of the blower speed. While such a control provides some improvement, its utility is limited for at least two reasons: (1) steady-state/transient coupling, and (2) environmental state ambiguity. The first reasonxe2x80x94steady-state/transient couplingxe2x80x94refers to the fact that the same control table values (i.e., the traces illustrated in FIG. 1B) are used during both steady-state and transient (i.e., cool-down and warm-up) operating conditions. Thus, adaptive changes made during steady-state operation also affect transient operation, and vice-versa. The second reasonxe2x80x94environmental state ambiguityxe2x80x94refers to the fact that any number of different environmental conditions can result in the same program number PN, and therefore, the same control response. Thus, adaptive changes made for one set of environmental conditions may well produce a response that is inappropriate for a different set of environmental conditions. Accordingly, what is desired is an improved adaptive climate control methodology that does not suffer from these limitations.
The present invention is directed to an improved motor vehicle automatic climate control methodology in which climate control commands are individually developed in response to ambient environmental conditions and a transient state estimator, and individually and adaptively adjusted to improve driver comfort in response to driver overrides of the respective automatic control settings. The adaptive adjustment of the climate control commands is carried out by CMAC Neural Networks that take into account the environmental conditions and the dynamic state of the system when the respective overrides occur so as to minimize or eliminate the environmental state ambiguity and steady-state/transient coupling that occur in currently known control methodologies.